Well compiler errors are never fun.
It looks like platformio didn’t complete the recursive dependency library installation correctly. That sometimes happens when it’s trying to install all the dependencies for ModularSensors at once.
You can check what libraries it did install in the .pio/libdeps/mayfly folder of your project. You might see some folders with names like _tmp_junk_. If you do, you can just delete them. When platformio attempts to download a library it first puts it in a temporary folder and then unpacks it and those remnants sometimes get left over when things go wrong.
To give it another chance to install the missing libraries, open up a new terminal in your project and type
pio lib install
. You should see it go through and check for dependencies and for each say “is already installed” or install it.
If you really can’t get it to install the libraries that way, you can install the dependencies one at a time with
pio lib install zzz
where zzz is the name of the library. You shouldn’t need to do that though.